# Copyright 2015 The TensorFlow Authors. All Rights Reserved. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. # ============================================================================== """Base class for N-D convolutional LSTM layers.""" import tensorflow.compat.v2 as tf from keras import activations from keras import backend from keras import constraints from keras import initializers from keras import regularizers from keras.engine import base_layer from keras.layers.rnn.base_conv_rnn import ConvRNN from keras.layers.rnn.dropout_rnn_cell_mixin import DropoutRNNCellMixin from keras.utils import conv_utils class ConvLSTMCell(DropoutRNNCellMixin, base_layer.BaseRandomLayer): """Cell class for the ConvLSTM layer. Args: rank: Integer, rank of the convolution, e.g. "2" for 2D convolutions. filters: Integer, the dimensionality of the output space (i.e. the number of output filters in the convolution). kernel_size: An integer or tuple/list of n integers, specifying the dimensions of the convolution window. strides: An integer or tuple/list of n integers, specifying the strides of the convolution. Specifying any stride value != 1 is incompatible with specifying any `dilation_rate` value != 1. padding: One of `"valid"` or `"same"` (case-insensitive). `"valid"` means no padding. `"same"` results in padding evenly to the left/right or up/down of the input such that output has the same height/width dimension as the input. data_format: A string, one of `channels_last` (default) or `channels_first`. It defaults to the `image_data_format` value found in your Keras config file at `~/.keras/keras.json`. If you never set it, then it will be "channels_last". dilation_rate: An integer or tuple/list of n integers, specifying the dilation rate to use for dilated convolution. Currently, specifying any `dilation_rate` value != 1 is incompatible with specifying any `strides` value != 1. activation: Activation function to use. If you don't specify anything, no activation is applied (ie. "linear" activation: `a(x) = x`). recurrent_activation: Activation function to use for the recurrent step. use_bias: Boolean, whether the layer uses a bias vector. kernel_initializer: Initializer for the `kernel` weights matrix, used for the linear transformation of the inputs. recurrent_initializer: Initializer for the `recurrent_kernel` weights matrix, used for the linear transformation of the recurrent state. bias_initializer: Initializer for the bias vector. unit_forget_bias: Boolean. If True, add 1 to the bias of the forget gate at initialization. Use in combination with `bias_initializer="zeros"`. This is recommended in [Jozefowicz et al., 2015]( http://www.jmlr.org/proceedings/papers/v37/jozefowicz15.pdf) kernel_regularizer: Regularizer function applied to the `kernel` weights matrix. recurrent_regularizer: Regularizer function applied to the `recurrent_kernel` weights matrix. bias_regularizer: Regularizer function applied to the bias vector. kernel_constraint: Constraint function applied to the `kernel` weights matrix. recurrent_constraint: Constraint function applied to the `recurrent_kernel` weights matrix. bias_constraint: Constraint function applied to the bias vector. dropout: Float between 0 and 1. Fraction of the units to drop for the linear transformation of the inputs. recurrent_dropout: Float between 0 and 1. Fraction of the units to drop for the linear transformation of the recurrent state. Call arguments: inputs: A (2+ `rank`)D tensor. states: List of state tensors corresponding to the previous timestep. training: Python boolean indicating whether the layer should behave in training mode or in inference mode. Only relevant when `dropout` or `recurrent_dropout` is used. """ def __init__( self, rank, filters, kernel_size, strides=1, padding="valid", data_format=None, dilation_rate=1, activation="tanh", recurrent_activation="hard_sigmoid", use_bias=True, kernel_initializer="glorot_uniform", recurrent_initializer="orthogonal", bias_initializer="zeros", unit_forget_bias=True, kernel_regularizer=None, recurrent_regularizer=None, bias_regularizer=None, kernel_constraint=None, recurrent_constraint=None, bias_constraint=None, dropout=0.0, recurrent_dropout=0.0, **kwargs, ): super().__init__(**kwargs) self.rank = rank if self.rank > 3: raise ValueError( f"Rank {rank} convolutions are not currently " f"implemented. Received: rank={rank}" ) self.filters = filters self.kernel_size = conv_utils.normalize_tuple( kernel_size, self.rank, "kernel_size" ) self.strides = conv_utils.normalize_tuple( strides, self.rank, "strides", allow_zero=True ) self.padding = conv_utils.normalize_padding(padding) self.data_format = conv_utils.normalize_data_format(data_format) self.dilation_rate = conv_utils.normalize_tuple( dilation_rate, self.rank, "dilation_rate" ) self.activation = activations.get(activation) self.recurrent_activation = activations.get(recurrent_activation) self.use_bias = use_bias self.kernel_initializer = initializers.get(kernel_initializer) self.recurrent_initializer = initializers.get(recurrent_initializer) self.bias_initializer = initializers.get(bias_initializer) self.unit_forget_bias = unit_forget_bias self.kernel_regularizer = regularizers.get(kernel_regularizer) self.recurrent_regularizer = regularizers.get(recurrent_regularizer) self.bias_regularizer = regularizers.get(bias_regularizer) self.kernel_constraint = constraints.get(kernel_constraint) self.recurrent_constraint = constraints.get(recurrent_constraint) self.bias_constraint = constraints.get(bias_constraint) self.dropout = min(1.0, max(0.0, dropout)) self.recurrent_dropout = min(1.0, max(0.0, recurrent_dropout)) self.state_size = (self.filters, self.filters) def build(self, input_shape): super().build(input_shape) if self.data_format == "channels_first": channel_axis = 1 else: channel_axis = -1 if input_shape[channel_axis] is None: raise ValueError( "The channel dimension of the inputs (last axis) should be " "defined. Found None. Full input shape received: " f"input_shape={input_shape}" ) input_dim = input_shape[channel_axis] self.kernel_shape = self.kernel_size + (input_dim, self.filters * 4) recurrent_kernel_shape = self.kernel_size + ( self.filters, self.filters * 4, ) self.kernel = self.add_weight( shape=self.kernel_shape, initializer=self.kernel_initializer, name="kernel", regularizer=self.kernel_regularizer, constraint=self.kernel_constraint, ) self.recurrent_kernel = self.add_weight( shape=recurrent_kernel_shape, initializer=self.recurrent_initializer, name="recurrent_kernel", regularizer=self.recurrent_regularizer, constraint=self.recurrent_constraint, ) if self.use_bias: if self.unit_forget_bias: def bias_initializer(_, *args, **kwargs): return backend.concatenate( [ self.bias_initializer( (self.filters,), *args, **kwargs ), initializers.get("ones")( (self.filters,), *args, **kwargs ), self.bias_initializer( (self.filters * 2,), *args, **kwargs ), ] ) else: bias_initializer = self.bias_initializer self.bias = self.add_weight( shape=(self.filters * 4,), name="bias", initializer=bias_initializer, regularizer=self.bias_regularizer, constraint=self.bias_constraint, ) else: self.bias = None self.built = True def call(self, inputs, states, training=None): h_tm1 = states[0] # previous memory state c_tm1 = states[1] # previous carry state # dropout matrices for input units dp_mask = self.get_dropout_mask_for_cell(inputs, training, count=4) # dropout matrices for recurrent units rec_dp_mask = self.get_recurrent_dropout_mask_for_cell( h_tm1, training, count=4 ) if 0 < self.dropout < 1.0: inputs_i = inputs * dp_mask[0] inputs_f = inputs * dp_mask[1] inputs_c = inputs * dp_mask[2] inputs_o = inputs * dp_mask[3] else: inputs_i = inputs inputs_f = inputs inputs_c = inputs inputs_o = inputs if 0 < self.recurrent_dropout < 1.0: h_tm1_i = h_tm1 * rec_dp_mask[0] h_tm1_f = h_tm1 * rec_dp_mask[1] h_tm1_c = h_tm1 * rec_dp_mask[2] h_tm1_o = h_tm1 * rec_dp_mask[3] else: h_tm1_i = h_tm1 h_tm1_f = h_tm1 h_tm1_c = h_tm1 h_tm1_o = h_tm1 (kernel_i, kernel_f, kernel_c, kernel_o) = tf.split( self.kernel, 4, axis=self.rank + 1 ) ( recurrent_kernel_i, recurrent_kernel_f, recurrent_kernel_c, recurrent_kernel_o, ) = tf.split(self.recurrent_kernel, 4, axis=self.rank + 1) if self.use_bias: bias_i, bias_f, bias_c, bias_o = tf.split(self.bias, 4) else: bias_i, bias_f, bias_c, bias_o = None, None, None, None x_i = self.input_conv(inputs_i, kernel_i, bias_i, padding=self.padding) x_f = self.input_conv(inputs_f, kernel_f, bias_f, padding=self.padding) x_c = self.input_conv(inputs_c, kernel_c, bias_c, padding=self.padding) x_o = self.input_conv(inputs_o, kernel_o, bias_o, padding=self.padding) h_i = self.recurrent_conv(h_tm1_i, recurrent_kernel_i) h_f = self.recurrent_conv(h_tm1_f, recurrent_kernel_f) h_c = self.recurrent_conv(h_tm1_c, recurrent_kernel_c) h_o = self.recurrent_conv(h_tm1_o, recurrent_kernel_o) i = self.recurrent_activation(x_i + h_i) f = self.recurrent_activation(x_f + h_f) c = f * c_tm1 + i * self.activation(x_c + h_c) o = self.recurrent_activation(x_o + h_o) h = o * self.activation(c) return h, [h, c] @property def _conv_func(self): if self.rank == 1: return backend.conv1d if self.rank == 2: return backend.conv2d if self.rank == 3: return backend.conv3d def input_conv(self, x, w, b=None, padding="valid"): conv_out = self._conv_func( x, w, strides=self.strides, padding=padding, data_format=self.data_format, dilation_rate=self.dilation_rate, ) if b is not None: conv_out = backend.bias_add( conv_out, b, data_format=self.data_format ) return conv_out def recurrent_conv(self, x, w): strides = conv_utils.normalize_tuple( 1, self.rank, "strides", allow_zero=True ) conv_out = self._conv_func( x, w, strides=strides, padding="same", data_format=self.data_format ) return conv_out def get_config(self): config = { "filters": self.filters, "kernel_size": self.kernel_size, "strides": self.strides, "padding": self.padding, "data_format": self.data_format, "dilation_rate": self.dilation_rate, "activation": activations.serialize(self.activation), "recurrent_activation": activations.serialize( self.recurrent_activation ), "use_bias": self.use_bias, "kernel_initializer": initializers.serialize( self.kernel_initializer ), "recurrent_initializer": initializers.serialize( self.recurrent_initializer ), "bias_initializer": initializers.serialize(self.bias_initializer), "unit_forget_bias": self.unit_forget_bias, "kernel_regularizer": regularizers.serialize( self.kernel_regularizer ), "recurrent_regularizer": regularizers.serialize( self.recurrent_regularizer ), "bias_regularizer": regularizers.serialize(self.bias_regularizer), "kernel_constraint": constraints.serialize(self.kernel_constraint), "recurrent_constraint": constraints.serialize( self.recurrent_constraint ), "bias_constraint": constraints.serialize(self.bias_constraint), "dropout": self.dropout, "recurrent_dropout": self.recurrent_dropout, } base_config = super().get_config() return dict(list(base_config.items()) + list(config.items())) class ConvLSTM(ConvRNN): """Abstract N-D Convolutional LSTM layer (used as implementation base). Similar to an LSTM layer, but the input transformations and recurrent transformations are both convolutional. Args: rank: Integer, rank of the convolution, e.g. "2" for 2D convolutions. filters: Integer, the dimensionality of the output space (i.e. the number of output filters in the convolution). kernel_size: An integer or tuple/list of n integers, specifying the dimensions of the convolution window. strides: An integer or tuple/list of n integers, specifying the strides of the convolution. Specifying any stride value != 1 is incompatible with specifying any `dilation_rate` value != 1. padding: One of `"valid"` or `"same"` (case-insensitive). `"valid"` means no padding. `"same"` results in padding evenly to the left/right or up/down of the input such that output has the same height/width dimension as the input. data_format: A string, one of `channels_last` (default) or `channels_first`. The ordering of the dimensions in the inputs. `channels_last` corresponds to inputs with shape `(batch, time, ..., channels)` while `channels_first` corresponds to inputs with shape `(batch, time, channels, ...)`. It defaults to the `image_data_format` value found in your Keras config file at `~/.keras/keras.json`. If you never set it, then it will be "channels_last". dilation_rate: An integer or tuple/list of n integers, specifying the dilation rate to use for dilated convolution. Currently, specifying any `dilation_rate` value != 1 is incompatible with specifying any `strides` value != 1. activation: Activation function to use. By default hyperbolic tangent activation function is applied (`tanh(x)`). recurrent_activation: Activation function to use for the recurrent step. use_bias: Boolean, whether the layer uses a bias vector. kernel_initializer: Initializer for the `kernel` weights matrix, used for the linear transformation of the inputs. recurrent_initializer: Initializer for the `recurrent_kernel` weights matrix, used for the linear transformation of the recurrent state. bias_initializer: Initializer for the bias vector. unit_forget_bias: Boolean. If True, add 1 to the bias of the forget gate at initialization. Use in combination with `bias_initializer="zeros"`. This is recommended in [Jozefowicz et al., 2015]( http://www.jmlr.org/proceedings/papers/v37/jozefowicz15.pdf) kernel_regularizer: Regularizer function applied to the `kernel` weights matrix. recurrent_regularizer: Regularizer function applied to the `recurrent_kernel` weights matrix. bias_regularizer: Regularizer function applied to the bias vector. activity_regularizer: Regularizer function applied to. kernel_constraint: Constraint function applied to the `kernel` weights matrix. recurrent_constraint: Constraint function applied to the `recurrent_kernel` weights matrix. bias_constraint: Constraint function applied to the bias vector. return_sequences: Boolean. Whether to return the last output in the output sequence, or the full sequence. (default False) return_state: Boolean Whether to return the last state in addition to the output. (default False) go_backwards: Boolean (default False). If True, process the input sequence backwards. stateful: Boolean (default False). If True, the last state for each sample at index i in a batch will be used as initial state for the sample of index i in the following batch. dropout: Float between 0 and 1. Fraction of the units to drop for the linear transformation of the inputs. recurrent_dropout: Float between 0 and 1. Fraction of the units to drop for the linear transformation of the recurrent state. """ def __init__( self, rank, filters, kernel_size, strides=1, padding="valid", data_format=None, dilation_rate=1, activation="tanh", recurrent_activation="hard_sigmoid", use_bias=True, kernel_initializer="glorot_uniform", recurrent_initializer="orthogonal", bias_initializer="zeros", unit_forget_bias=True, kernel_regularizer=None, recurrent_regularizer=None, bias_regularizer=None, activity_regularizer=None, kernel_constraint=None, recurrent_constraint=None, bias_constraint=None, return_sequences=False, return_state=False, go_backwards=False, stateful=False, dropout=0.0, recurrent_dropout=0.0, **kwargs, ): cell = ConvLSTMCell( rank=rank, filters=filters, kernel_size=kernel_size, strides=strides, padding=padding, data_format=data_format, dilation_rate=dilation_rate, activation=activation, recurrent_activation=recurrent_activation, use_bias=use_bias, kernel_initializer=kernel_initializer, recurrent_initializer=recurrent_initializer, bias_initializer=bias_initializer, unit_forget_bias=unit_forget_bias, kernel_regularizer=kernel_regularizer, recurrent_regularizer=recurrent_regularizer, bias_regularizer=bias_regularizer, kernel_constraint=kernel_constraint, recurrent_constraint=recurrent_constraint, bias_constraint=bias_constraint, dropout=dropout, recurrent_dropout=recurrent_dropout, dtype=kwargs.get("dtype"), ) super().__init__( rank, cell, return_sequences=return_sequences, return_state=return_state, go_backwards=go_backwards, stateful=stateful, **kwargs, ) self.activity_regularizer = regularizers.get(activity_regularizer) def call(self, inputs, mask=None, training=None, initial_state=None): return super().call( inputs, mask=mask, training=training, initial_state=initial_state ) @property def filters(self): return self.cell.filters @property def kernel_size(self): return self.cell.kernel_size @property def strides(self): return self.cell.strides @property def padding(self): return self.cell.padding @property def data_format(self): return self.cell.data_format @property def dilation_rate(self): return self.cell.dilation_rate @property def activation(self): return self.cell.activation @property def recurrent_activation(self): return self.cell.recurrent_activation @property def use_bias(self): return self.cell.use_bias @property def kernel_initializer(self): return self.cell.kernel_initializer @property def recurrent_initializer(self): return self.cell.recurrent_initializer @property def bias_initializer(self): return self.cell.bias_initializer @property def unit_forget_bias(self): return self.cell.unit_forget_bias @property def kernel_regularizer(self): return self.cell.kernel_regularizer @property def recurrent_regularizer(self): return self.cell.recurrent_regularizer @property def bias_regularizer(self): return self.cell.bias_regularizer @property def kernel_constraint(self): return self.cell.kernel_constraint @property def recurrent_constraint(self): return self.cell.recurrent_constraint @property def bias_constraint(self): return self.cell.bias_constraint @property def dropout(self): return self.cell.dropout @property def recurrent_dropout(self): return self.cell.recurrent_dropout def get_config(self): config = { "filters": self.filters, "kernel_size": self.kernel_size, "strides": self.strides, "padding": self.padding, "data_format": self.data_format, "dilation_rate": self.dilation_rate, "activation": activations.serialize(self.activation), "recurrent_activation": activations.serialize( self.recurrent_activation ), "use_bias": self.use_bias, "kernel_initializer": initializers.serialize( self.kernel_initializer ), "recurrent_initializer": initializers.serialize( self.recurrent_initializer ), "bias_initializer": initializers.serialize(self.bias_initializer), "unit_forget_bias": self.unit_forget_bias, "kernel_regularizer": regularizers.serialize( self.kernel_regularizer ), "recurrent_regularizer": regularizers.serialize( self.recurrent_regularizer ), "bias_regularizer": regularizers.serialize(self.bias_regularizer), "activity_regularizer": regularizers.serialize( self.activity_regularizer ), "kernel_constraint": constraints.serialize(self.kernel_constraint), "recurrent_constraint": constraints.serialize( self.recurrent_constraint ), "bias_constraint": constraints.serialize(self.bias_constraint), "dropout": self.dropout, "recurrent_dropout": self.recurrent_dropout, } base_config = super().get_config() del base_config["cell"] return dict(list(base_config.items()) + list(config.items())) @classmethod def from_config(cls, config): return cls(**config)